My upcoming scanner antenna install.

[CopperWhopper67]

Hello all,

After 4 years of sitting in my closet disassembled, my Tram 1411 Discone is going to be installed on top of my building, and I am looking for some advice to do it right so I don't have to go back up on that sketchy roof after it's done.

First some info:

• I already have 50 ft of RG-8X from when I got the antenna originally
• Depending on how I run the cable, the final length from antenna to equipment will be anywhere from 30-50ft
  • This building has a prominent gambrel roof that covers the entire 2nd level, which means I can either tap a hole in my roof and lead the cable directly down the wall by my desk totaling 30ft, or I would have to run the cable down the roof to the 1st level and back up into the living space on level 2, adding almost 15-20ft of cable (45-50ft total).
• This will be a largely Rx only system, with a small possibility of some very light 2m/70cm Tx-ing in the distant future.
• Equipment connected will almost exclusively consist of Uniden SDS200 scanner and/or an SDR (Only 1 device will be connected at a time currently, because I don't want to pay for a multi-coupler at this time)
• Fortunately my location is pretty advantageous; I live on top of a hill, and the building is 23ft tall; the antenna will sit atop a 10ft steel conduit strapped to a 3ft J-Pole, mounted near the roof's peak. (If you can recommend a better mounting solution, please do.)
• I wish to explore the spectrum as much as I can between 30 and 900 Mhz with the SDR, as well as scan public safety with the Uniden (CHP, Local Agencies on VHF, plus the Sacramento 800Mhz P25 System [Whose nearest site is about 10 miles away]) {Also, being able to receive some HF would be cool too, but I understand that it is not likely}

Here are my questions:

1. Is this even the proper antenna for my wants/needs? Are there others I should consider?
2. If this antenna is a good one, should I use the top aerial or leave it off?
3. Would it be worth it to punch through the roof for the shorter run? If so, how would I seal the opening?
4. Is my current RG-8X sufficient for either length? Should I get better cable?
5. Would getting a preamp be a good idea?
6. How should I implement a lightning arrester?

Let me know if you need any more info.

Thanks!

 

[popnokick]

Is this even the proper antenna for my wants/needs? Are there others I should consider?

1. If this antenna is a good one, should I use the top aerial or leave it off?
2. Would it be worth it to punch through the roof for the shorter run? If so, how would I seal the opening?
3. Is my current RG-8X sufficient for either length? Should I get better cable?
4. Would getting a preamp be a good idea?
5. How should I implement a lightning arrester?

Thanks!

1. If you're planning to transmit at all then keep the discone and leave the top aerial on. Wideband discones are capable of transmit operation.
2. If you have any doubts about sealing the roof after putting a hole in it, DON'T. IMHO would be to avoid a roof penetration.
3. Ditch the RG-8X. Losses are too high above 400 mHz, particularly if possible transmit in future. Consider LMR-400 or better especially since you'll be using greater length (See answer to #2)
4. Don't get preamp until you see how the entire setup performs without one. And realize that if you get a preamp in the future and transmit into it you will destroy the preamp.
5. Per NEC guidelines for residential antennas and lightning protection. Too voluminous to detail here; much has been written here on RR and also available online.

 

[mmckenna]

1. How should I implement a lightning arrester?

This should give you a starting point:

https://www.mikeholt.com/instructor2/img/product/pdf/17LED-1498-sample.pdf

 

[CopperWhopper67]

1. If you're planning to transmit at all then keep the discone and leave the top aerial on.

Transmit will probably be a year away at the least. Should I still keep it?

Will that aerial affect my Rx freq range?

3. Ditch the RG-8X. Losses are too high above 400 mHz, particularly if possible transmit in future. Consider LMR-400 or better especially since you'll be using greater length (See answer to #2)

On Amazon I am seeing listings for "Bolton400 LMR 400 Equivalent" for a good price. Is that sufficient or should I just pay the extra for the actual TMS brand stuff?

Thanks!

 

[ladn]

On Amazon I am seeing listings for "Bolton400 LMR 400 Equivalent" for a good price. Is that sufficient or should I just pay the extra for the actual TMS brand stuff?

A lot of these "LMR 400 equivalent" cables are of questionable quality. The only equivalency may be that they're the same dimeter. Think "Baofeng" in a coax. Buy real LMR 400 from a reputable vendor.

 

[mmckenna]

On Amazon I am seeing listings for "Bolton400 LMR 400 Equivalent" for a good price. Is that sufficient or should I just pay the extra for the actual TMS brand stuff?

Yeah, I agree with ladn. There are some good Times Microwave LMR-400 equivalents out there, but there's also some trash. I'd really pay attention to what others have used. Amazon reviews are often pretty useless, as you never know what the reviewers experience level is, or what other coax cables they are comparing to.

Considering you'll be using this coax for a long time, and having quality cable (as well as connectors) is -really- important, it's rarely a good investment to cut corners on it. Paying a bit more for the real stuff can be worth it unless you know for sure what you are getting.

 

[CopperWhopper67]

A lot of these "LMR 400 equivalent" cables are of questionable quality. The only equivalency may be that they're the same dimeter. Think "Baofeng" in a coax. Buy real LMR 400 from a reputable vendor.

Thanks for all the info, folks! What are some good vendors out there for cable on connectors?

 

[sallen07]

Thanks for all the info, folks! What are some good vendors out there for cable on connectors?

The Antenna Farm. You can get standard lengths or they will custom-make whatever length and connectors you want.

The Antenna Farm, Your two way radio source

The Antenna Farm : - VHF & UHF Mobile Radios Radio Accessories VHF & UHF Hand Held Radios Antennas Mobile Antenna Mounts SWR/Power Meters Adapters Coaxial Cable Two Way Accessories Antenna Accessories DC Power Supplies Coax Cable Accessories Connectors Aviation Radios Repeater Systems Towers &...

www.theantennafarm.com

 

[CopperWhopper67]

The Antenna Farm. You can get standard lengths or they will custom-make whatever length and connectors you want.

The Antenna Farm, Your two way radio source

The Antenna Farm : - VHF & UHF Mobile Radios Radio Accessories VHF & UHF Hand Held Radios Antennas Mobile Antenna Mounts SWR/Power Meters Adapters Coaxial Cable Two Way Accessories Antenna Accessories DC Power Supplies Coax Cable Accessories Connectors Aviation Radios Repeater Systems Towers &...

www.theantennafarm.com

Thank you

I had no idea they did more than just antennas.